In known techniques, optical character recognition (OCR) is performed for a character string contained in a recorded video, and a translation of the recognized character string) is then displayed in real time via superimposition on the recorded video. For example, Patent Literature 1 discloses an information display device in which a character string contained in, for example, a document or signboard is photographed by a camera and is then converted either into (i) a translation of the character string, through use of a dictionary, or (ii) other related information. The translation or the related information is then displayed via replacement of or superimposition on the original character string.